Chlorinated polyolefin impact modifier for vinyl chloride polymers

ABSTRACT

Chlorinated olefin polymers prepared from olefin polymer base resins having I 10  values of 0.05-0.8 dg/minute act as impact modifiers for vinyl chloride polymers under low to ambient temperature conditions. When vinyl chloride polymers are mixed with a preferred class of the chlorinated polymers, having chlorine contents of 20-30 percent by weight, compositions that exhibit short fusion times and low fusion temperatures are produced.

FIELD OF THE INVENTION

[0001] This invention relates to improved impact-resistant vinylchloride polymer compositions. More specifically, this invention relatesto blends of chlorinated polyolefin impact modifiers and vinyl chloridepolymers, especially polyvinyl-chloride.

BACKGROUND OF THE INVENTION

[0002] Polyvinyl chloride (PVC) is widely used in both its rigid andflexible forms in such applications as films, siding, sheets, pipe andtubing. Because rigid PVC is a hard, brittle thermoplastic polymer, itis often mixed with a modifier to form a composition that is less proneto failure on impact. For example, in U.S. Pat. Nos. 3,006,889 and3,209,055 the use of a broad range of chlorinated and chlorosulfonatedpolyethylenes in blends with PVC is disclosed. In addition, varioustypes of specialty chlorinated polyethylenes have been used as impactmodifiers. For example, chlorinated polyethylenes having low blockingtendencies that are prepared from polyolefins having melt indexes (I₂)of 0.3 dg/minute and 0.2 dg/minute are disclosed as impact modifiers forPVC in U.S. Pat. No. 4,767,823. Further, impact modifiers that aremixtures of chlorinated polyethylenes with other polymers have beendisclosed. As an example, Aono et al., in Japanese Unexamined PatentApplication Hei 7-11085, disclose the use of a mixture of a chlorinatedpolyethylene prepared from a polyethylene of molecular weight 50,000 to400,000 and AES resin (acrylonitrile-EPDM-styrene), optionally incombination with other polymers, as an impact modifier for PVC.

[0003] Despite the extensive prior art that exists related tochlorinated polyethylene impact modification of PVC, economicalcompositions that exhibit exceptionally good impact strengths in theambient to low temperature range have not been disclosed. Suchcompositions would be useful in applications such as siding, profilesand pipe.

[0004] Impact strength is not the only physical property of PVC that canbe improved by addition of chlorinated polymeric additives. For example,in U.S. Pat. No. 4,481,133 a method for improving extrudability ofPVC/chlorinated polyethylene blends is disclosed that involves mixingPVC with chlorinated polyethylene of molecular weight 10,000 to12,000,000 (preferably 60,000 to 500,000), and a fluoropolymer. Thebenefits of blending PVC with more than one type of chlorinatedpolyethylene are disclosed by Klug, et al. in U.S. Pat. No. 4,280,940.The Klug reference discloses an easily processed blend of PVC and twochlorinated polyethylenes, where the first chlorinated polyethylene isprepared from polyethylene having a melt flow index 190/5 (i.e. I₅ at190° C.) of preferably 0.3-3.5 g/10 minutes (0.3-3.5 dg/minute) and thesecond chlorinated polyethylene is prepared from polyethylene having amelt flow index 190/5 preferably of from 40-55 g/10 minutes (40-55dg/minute).

[0005] With regard to PVC compositions useful in the ambient to lowtemperature range, it would be desirable to have a composition that ischaracterized by excellent impact resistance in combination with ease ofpreparation. Efficient manufacture of PVC/additive compositions requiresthat the blends exhibit an appropriately low fusion temperature andfusion time. Fusion temperature refers to the temperature at which amixture of PVC and an additive form a homogeneous system. In order toincorporate an additive into PVC, it is necessary to heat the PVC whileblending in the additive. Short fusion times and low temperatures aredesirable because PVC is susceptible to decomposition at melttemperatures. An impact modifier that has a low fusion temperature andshort fusion time would consequently have definite processing advantagesin manufacture of PVC compositions.

SUMMARY OF THE INVENTION

[0006] The present invention is specifically directed to an improvedvinyl chloride composition having excellent impact strength. Inparticular, the impact resistant composition comprises a) a vinylchloride polymer and b) an impact modifier, wherein said impact modifiercomprises a polymer consisting of a chlorinated olefin polymer having achlorine content of from 15-39 percent by weight; said chlorinatedolefin polymer being prepared from an olefin polymer selected from thegroup consisting of i) polyethylene homopolymers having I₁₀ values offrom 0.05-0.8 dg/minute and ii) copolymers of ethylene and up to 10 molepercent of a copolymerizable monomer, said copolymers having I₁₀ valuesof from 0.05-0.8 dg/minute; and wherein no more than 1 weight percent ofa chlorinated olefin polymer having a weight average molecular weightbelow 200,000 daltons is present in the impact resistant composition.

[0007] In a preferred embodiment, the chlorinated olefin polymer has achlorine content of 20 to 30 percent by weight. Such compositionsexhibit low fusion temperatures and short fusion times.

DETAILED DESCRIPTION OF THE INVENTION

[0008] The impact resistant compositions of the present inventioncomprise a vinyl chloride polymer and a chlorinated olefin polymerhaving specific chemical composition and physical properties.

[0009] The vinyl chloride polymer component is a solid, high molecularweight polymer that may be a polyvinyl chloride homopolymer or acopolymer of vinyl chloride having copolymerized units of one or moreadditional comonomers. When present, such comonomers will account for upto 20 weight percent of the copolymer, preferably from 1-5 weightpercent of the copolymer. Examples of suitable comonomers include C₂-C₁₀olefins, for example ethylene and propylene; vinyl esters of straightchain or branched C₂-C₄ carboxylic acids, such as vinyl acetate, vinylpropionate, and vinyl 2-ethyl hexanoate; vinyl halides, for examplevinyl fluoride, vinylidene fluoride or vinylidene chloride; vinylethers, such as vinyl methyl ether and butyl vinyl ether; vinylpyridine; unsaturated acids, for example maleic acid, fumaric acid,methacrylic acid and their mono- or diesters with C₁-C₁₀ mono- ordialcohols; maleic anhydride, maleic acid imide as well as theN-substitution products of maleic acid imide with aromatic,cycloaliphatic and optionally branched aliphatic substituents;acrylonitrile and styrene. Such homopolymers and interpolymerizedcopolymers are commercially available from Borden Chemicals andPlastics. They may also be prepared by any suitable polymerizationmethod. Polymers. prepared using a suspension process are preferred.

[0010] Graft copolymers of vinyl chloride are also suitable for use inthe invention. For example, ethylene copolymers, such as ethylene vinylacetate, and ethylene copolymer elastomers, such as EPDM (copolymerscomprising copolymerized units of ethylene, propylene and dienes) andEPR (copolymers comprising copolymerized units of ethylene andpropylene) that are grafted with vinyl chloride may be used as the vinylchloride polymer component. A commercially available example of such apolymer is Vinnol® 550, available from Wacker Chemie GmbH.

[0011] The chlorinated olefin polymer component of the compositions ofthe invention is selected from the group consisting of a) chlorinatedpolyethylene homopolymers prepared from polyethylenes having an I₁₀value of from 0.05-0.8 dg/minute and b) chlorinated copolymers preparedfrom polyolefins having an I₁₀ value of from 0.05-0.8 dg/minute thatcontain copolymerized units of i) ethylene and ii) up to 10 mole percentof a copolymerizable monomer. The chlorinated olefin polymer mayoptionally contain chlorosulfonyl groups. That is, the polymer chainwill have pendant chlorine groups and chlorosulfonyl groups. Suchpolymers are known as chlorosulfonated olefin polymers.

[0012] Representative chlorinated and chlorosulfonated olefin polymersinclude a) chlorinated and chlorosulfonated homopolymers of ethylene andb) chlorinated and chlorosulfonated copolymers of ethylene and at leastone ethylenically unsaturated monomer selected from the group consistingof C₃-C₁₀ alpha monoolefins; C₁-C₁₂ alkyl esters of C₃-C₂₀monocarboxylic acids; unsaturated C₃-C₂₀ mono- or dicarboxylic acids;anhydrides of unsaturated C₄-C₈ dicarboxylic acids; and vinyl esters ofsaturated C₂-C₁₈, carboxylic acids. Chlorinated and chlorosulfonatedgraft copolymers are included as well. Specific examples of suitablepolymers include chlorinated polyethylene; chlorosulfonatedpolyethylene; chlorinated ethylene vinyl acetate copolymers;chlorosulfonated ethylene vinyl acetate copolymers; chlorinated ethyleneacrylic acid copolymers; chlorosulfonated ethylene acrylic acidcopolymers; chlorinated ethylene methacrylic acid copolymers;chlorosulfonated ethylene methacrylic acid copolymers; chlorinatedethylene methyl acrylate copolymers; chlorinated ethylene methylmethacrylate copolymers; chlorinated ethylene n-butyl methacrylatecopolymers; chlorinated ethylene glycidyl methacrylate copolymers;chlorinated graft copolymers of ethylene and maleic acid anhydride;chlorinated copolymers of ethylene with propylenq, butene,3-methyl-1-pentene, or octene and chlorosulfonated copolymers ofethylene with propylene, butene, 3-methyl-1-pentene or octene. Thecopolymers may be dipolymers, terpolymers, or higher order copolymers.Preferred chlorinated olefin polymers are-chlorinated polyethylene andchlorinated copolymers of ethylene vinyl acetate.

[0013] A particular feature of the chlorinated olefin polymers of thepresent invention is that they are prepared from polyolefin base resinshaving relatively high molecular weights. That is, the polyolefin baseresins are characterized by having I₁₀ melt index values of from 0.05dg/minute to 0.8 dg/minute, preferably from 0.3-0.8 dg/minute, mostpreferably from 0.5-0.8 dg/minute. I₁₀ melt indices within the broadrange of 0.05-0.8 dg/minute correspond generally to weight averagemolecular weights of 400,000-1,000,000 daltons. Olefin polymers havingI₁₀ melt indices below 0.05 are difficult to manufacture. Olefinpolymers having I₁₀ melt indices above 0.8 dg/minute are inferior inimpact performance.

[0014] The chlorinated and chlorosulfonated olefin polymers useful inthe practice of the invention contain 15-39 weight percent chlorine,preferably 20-30 weight percent chlorine. Because the molecular weightof the non-chlorinated polyolefin base resins is from approximately400,000-1,000,000 daltons, the chlorinated and chlorosulfonated olefinpolymers will be of relatively high molecular weight. If the chlorinatedolefin polymer is chlorosulfonated, it will generally have a sulfurcontent of up to 6 wt. %, preferably 1-3 wt. %. It is a further featureof the invention that the impact resistant compositions contain lessthan 1 wt. %, based on the weight of the chlorinated olefin polymer, ofa chlorinated olefin polymer of low molecular weight, i.e. having aweight average molecular weight below 200,000 daltons.

[0015] The chlorinated olefin polymers and chlorosulfonated olefinpolymers suitable for use in the impact resistant compositions of theinvention may be prepared from polyolefin resins that are branched orunbranched. The polyolefin base resins may be prepared by free radicalprocesses, Ziegler-Natta catalysis or catalysis with metallocenecatalyst systems, for example those disclosed in U.S. Pat. Nos.5,272,236 and 5,278,272. Chlorination or chlorosulfonation of the baseresins may take place in suspension, solution, solid state or fluidizedbed. Free radical suspension chlorination processes are described andtaught in U.S. Pat. No. 3,454,544, U.S. Pat. No. 4,767,823 andreferences cited therein. Such processes involve preparation of anaqueous suspension of a finely divided ethylene polymer which is thenchlorinated. An example of a free radical solution chlorination processis disclosed in U.S. Pat. No. 4,591,621. The polymers may also bechlorinated in the melt or fluidized beds, for example as taught in U.S.Pat. No. 4,767,823. Chlorosulfonation processes are generally performedin solution but suspension and non-solvent processes are also known.Preparation of chlorosulfonated olefin polymers is described in U.S.Pat. Nos. 2,586,363; 3,296,222; 3,299,014; and 5,242,987.

[0016] The impact resistant compositions of the invention will generallycomprise 2-20 parts by weight of the chlorinated or chlorosulfonatedolefin polymer per 100 parts by weight of vinyl chloride polymer.Preferably, 2-15 parts by weight (and most preferably 2-8 parts byweight) of the chlorinated or chlorosulfonated olefin polymer per 100parts by weight of the vinyl chloride polymer is used because this levelprovides compositions having a good combination of impact modificationand stiffness. Compositions containing more than 20 parts by weight ofthe chlorinated or chlorosulfonated polymer are characterized by lowmodulus, resulting in poor dimensional stability.

[0017] The impact resistant compositions of the present invention arephysical blends of polymers and do not require crosslinking orvulcanization in order to be useful as commercial products. However, thecompositions can additionally contain compounding ingredients such asstabilizers, blowing agents, lubricants, colorants, fillers,crosslinking agents, process aids and the like. The use of suchadditional components permits the compositions to be tailored for use invarious applications, for example rigid PVC profiles such as siding,windows, fencing, decking and pipe. Particularly useful compoundingingredients include tin stabilizers, calcium carbonate, titaniumdioxide, acrylic process aids, and hydrocarbon and ester waxes. Ifcompounding ingredients are utilized, they are generally used in amountsof from 0.1-30 parts per 100 parts vinyl chloride resin, depending onthe type of additive. For example, fillers are generally used in amountsof 2-25 parts per 100 parts vinyl chloride polymer.

[0018] In a preferred embodiment, the chlorine content of thechlorinated olefin polymer ranges from 20 to 30 percent by weight. Suchcompositions exhibit a particularly favorable combination of low fusiontemperature and short fusion time. That is, when such polymers areblended with vinyl chloride polymers, generally by a process thatinvolves feeding the polymeric components as.powders to an extruder andprocessing at melt temperatures of 160° C.-220° C., a homogenous mixturewill be formed within approximately five minutes. When chlorinatedpolymers of the invention having chlorine contents of 20-30 wt. % areutilized as blend components, extrusion temperatures can be maintainedat the lower end of this range, i.e. generally from 160° C.-200° C. Thisresults in little or no polymer degradation and rapid production of theimpact resistant compositions of the invention.

[0019] The impact-resistant compositions of this invention may furthercomprise one or more additional polymers (such as acrylonitrile oracrylate polymers) to provide a preferred composition. Examples of suchpolymers include, but are not limited to acrylonitrile butadiene styrenecopolymers (ABS), available from Rohm and Haas Co.; and methacrylatebutadiene styrene copolymers (MBS); polyacrylates, such as Paraloid™KM-334 acrylic impact modifier (available from Rohm and Haas Company)and modified acrylic polymers, such as Durastrength® 200 acrylic impactmodifier (available from ATOFINA). The additional polymer component orcomponents are preferably present in amounts of no more than 200 partsper 100 parts of chlorinated olefin polymer. Impact resistantcompositions of the invention that contain the additional polymericcomponent typically contain between 1 to 20 parts by weight of theadditional component per 100 parts by weight of vinyl chloride polymer.

[0020] The impact resistant compositions of the present invention areparticularly useful in the manufacture of PVC siding and windowprofiles.

[0021] The invention is further illustrated by the following embodimentswherein all parts are by weight unless otherwise indicated.

EXAMPLES Example 1

[0022] A PVC masterbatch composition, Masterbatch A, was prepared in aWelex high intensity mixer according to the following procedure: 100parts PVC was added to the mixer and the contents were mixed and heateduntil the temperature reached 120° F. (49° C.). One part of Advastab®TM-281, a tin stabilizer available from Rohm and Haas Company, was thenadded and mixing was continued. When a temperature of 165° F. (74° C.)was reached 1 part of calcium stearate was-added. This was followed byaddition of 1 part of TiPure® R960 titanium dioxide (available from E.I. du Pont de Nemours and Co.) and 15 parts Omyacarb® UFT calciumcarbonate (available from Omya, Inc.) when the temperature reached 190°F. (88° C.). Mixing was continued until a temperature of 225° F. (107°C.) was reached. The speed of the mixer was then lowered to the minimumand the mixer was cooled externally. When the temperature of the mixturereached 120° F. (49° C.), it was removed. Approximately 6000 g ofmasterbatch was collected.

[0023] A chlorinated polyethylene, CPE-1, having a chlorine content of34.6 wt. % and a heat of fusion (an indicator of residual crystallinity)of 0.14 cal/g was prepared in a slurry process from a polyethylenehaving a melt index (I₁₀) of 0.6 dg/minute, substantially according tothe procedure described in U.S. Pat. No. 4,767,823 and references citedtherein.

[0024] A composition of the invention, Sample 1-1, was prepared bymixing 118 parts of Masterbatch A; 4 parts of CPE-1; 1.2 parts ofHostalub® XL 165 paraffin wax (available from Clariant Corporation); and0.2 parts A-C® 316 oxidized polyethylene (available from HoneywellInternational, Inc.) in a stainless steel blender for one minute. A 67 gsample of the resultant blended mixture was placed in a Haake Rheocord®90 torque rheometer set at 60 rpm and a 1800° C. bowl temperature.Mixing continued until a totalized torque value (i.e. the integratedarea under the torque vs. time curve) of 10 meter-kg-minute was reached.The bowl was then removed and the sample was collected. The total samplewas pressed in a PHI hydraulic press using a 125 mil thick chase at 374°F. (1900° C.). The sample was preheated for 5 minutes, pressed for 5minutes at 20 tons pressure, and then cooled under 20 tons pressure.Rectangular notched Izod test specimens were die cut from thecompression molded plaque. The specimens were notched with a TMInotching cutter and the thickness of each specimen was measured at thepoint of the notch. The test specimens were then broken using a TiniusOlsen Plastics Impact Tester at room temperature and the impact strengthcalculated. Six test specimens were broken and the impact strength wastaken as the average. Test specimens that failed in a ductile mannerwere noted and the number that failed in this manner was recorded.Results are shown in Table I. Eight other samples of the invention,Samples 1-2 through 1-9, were prepared substantially as described aboveexcept that the amounts of CPE-1 and paraffin wax were varied as shownin Table I.

[0025] The results show that 89of the samples tested for Izod impact atroom temperature exhibited ductile failure, rather than brittle break.TABLE I Sample Sample Sample Sample Sample Sample Sample Sample SampleFormulation 1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9 Masterbatch A 118 118118 118 118 118 118 118 118 CPE-1 4.0 4.5 5.0 4.0 4.5 5.0 4.0 4.5 5.0Paraffin Wax 1.2 1.2 1.2 1.4 1.4 1.4 1.6 1.6 1.6 Oxidized PE 0.2 0.2 0.20.2 0.2 0.2 0.2 0.2 0.2 Notched Izod 3/6 5/6 5/6 5/6 6/6 6/6 6/6 6/6 6/6Ductile Failures

Example 2

[0026] A chlorinated polyethylene, CPE-2, having a chlorine content of36.1 wt. % and a heat of fusion of 0.27 cal/g, was prepared in a slurryprocess from a polyethylene having a melt index (I₁₀) of 0.1 dg/minute,substantially according to the procedure described in U.S. Pat. No.4,767,823 and references cited therein. A composition of the invention,Sample 2-1, was prepared substantially as described in Example 1 bymixing 118 parts of Masterbatch A; 4 parts of CPE-2; 1.2 parts ofHostalub® XL 165 paraffin wax (available from Clariant Corporation); and0.2 parts A-C® 316 oxidized polyethylene (available from HoneywellInternational, Inc.). Notched Izod test specimens were prepared asdescribed in Example 1. Six test specimens were broken and the impactstrength was taken as the average. Test specimens that failed in aductile manner were noted and the number that failed in this manner wererecorded. Results are shown in Table II. Eight other samples of theinvention, Samples 2-2 through 2-9, were prepared in substantially thesame manner except that the amounts of CPE-2 and paraffin wax werevaried as shown in Table II.

[0027] The results show that 96% of the samples tested for Izod impactat room temperature exhibited ductile failure, rather than brittlebreak. TABLE II Sample Sample Sample Sample Sample Sample Sample SampleSample Formulation 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 Masterbatch A 118118 118 118 118 118 118 118 118 CPE-2 4.0 4.5 5.0 4.0 4.5 5.0 4.0 4.55.0 Paraffin Wax 1.2 1.2 1.2 1.4 1.4 1.4 1.6 1.6 1.6 Oxidized PE 0.2 0.20.2 0.2 0.2 0.2 0.2 0.2 0.2 Notched Izod 6/6 6/6 6/6 6/6 5/6 6/6 6/6 5/66/6 Ductile Failures

Comparative Example A

[0028] A chlorinated polyethylene, CPE-3, having a chlorine content of36 wt. % and a heat of fusion of less than 0.2 cal/g was prepared in aslurry process from a polyethylene having a melt index (I₁₀) of 3.13dg/minute, substantially according to the procedure described in U.S.Pat. No. 4,767,823 and references cited therein. Comparative Sample A-1was prepared substantially as described in Example 1 by mixing 118 partsof Masterbatch A; 4 parts of CPE-3; 1.2 parts of Hostalub® XL 165paraffin wax (available from Clariant Corporation); and 0.2 parts A-C®316 oxidized polyethylene (available from Honeywell International,Inc.). Notched Izod test specimens were prepared as described inExample 1. Six test specimens were broken and the impact strength wastaken as the average. Test specimens that failed in a ductile mannerwere noted and the number that failed in this manner were recorded.Results are shown in Table III. Eight other comparative samples SamplesA-2 through A-9, were prepared in substantially the same manner exceptthat the amounts of CPE-3 and paraffin wax were varied as shown in TableIII.

[0029] The results show that 59% of the samples tested for Izod impactat room temperature exhibited ductile failure, rather than brittlebreak. TABLE III Sample Sample Sample Sample Sample Sample Sample SampleSample Formulation A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 Masterbatch A 118118 118 118 118 118 118 118 118 CPE-3 4.0 4.5 5.0 4.0 4.5 5.0 4.0 4.55.0 Paraffin Wax 1.2 1.2 1.2 1.4 1.4 1.4 1.6 1.6 1.6 Oxidized PE 0.2 0.20.2 0.2 0.2 0.2 0.2 0.2 0.2 Notched Izod 1/6 2/6 3/6 2/6 6/6 4/6 4/6 6/64/6 Ductile Failures

Comparative Example B

[0030] A chlorinated polyethylene, CPE-4, having a chlorine content of36.1 wt. % and a heat of fusion of 0.18 cal/g was prepared in a slurryprocess from a polyethylene having a melt index (I₁₀) of 1.45 dg/minute,substantially according to the procedure described in U.S. Pat. No.4,767,823 and references cited therein. Comparative Sample B-1 wasprepared substantially as described in Example 1 by mixing 118 parts ofMasterbatch A; 4 parts of CPE-4; 1.2 parts of Hostalub® XL 165 paraffinwax (available from Clariant Corporation); and 0.2 parts A-C® 316oxidized polyethylene (available from Honeywell International, Inc.).Notched Izod test specimens were prepared as described in Example 1. Sixtest specimens were broken and the impact strength was taken as theaverage. Test specimens that failed in a ductile manner were noted andthe number that failed in this manner were recorded. Results are shownin Table IV. Eight other comparative samples Samples B-2 through B-9,were prepared in substantially the same manner except that the amountsof CPE-4 and paraffin wax were varied as shown in Table IV.

[0031] The results show that 76% of the samples tested for Izod impactat room temperature exhibited ductile failure, rather than brittlebreak. TABLE IV Sample Sample Sample Sample Sample Sample Sample SampleSample Formulation B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8 B-9 Masterbatch A 118118 118 118 118 118 118 118 118 CPE-4 4.0 4.5 5.0 4.0 4.5 5.0 4.0 4.55.0 Paraffin Wax 1.2 1.2 1.2 1.4 1.4 1.4 1.6 1.6 1.6 Oxidized PE 0.2 0.20.2 0.2 0.2 0.2 0.2 0.2 0.2 Notched Izod 4/6 5/6 4/6 3/6 3/6 5/6 6/6 6/65/6 Ductile Failures

Example 3

[0032] A PVC masterbatch composition, Masterbatch B, was prepared in aWelex high intensity mixer according to the following procedure: 100parts PVC was added to the mixer and the contents were heated until thetemperature reached 120° F. (49° C). 1.5 parts of Thermolite®-137, a tinstabilizer available from Elf Atochem North America, Inc. was then addedand blending was continued until a temperature of 165° F. (74° C.) wasreached, at which point 0.92 parts calcium stearate, 1 part Hostlube®XL-165 paraffin wax (available from Clariant Corp.), and 1 partParaloid™ K120N acrylic process aid (available from Rohm and Haas Co.)were added. When the temperature reached 190° F. (88° C.), 10 parts ofTiPure® R960 titanium dioxide (available from E. I. du Pont de Nemoursand Co.) and 5 parts omyacarb® UFT calcium carbonate (available fromOmya, Inc.) were added. Blending was continued until a temperature of225° F. (107° C.) was reached. The speed of the mixer was lowered to theminimum and the mixer was cooled externally. When the temperature of themixture reached 120° F. (49° C.), it was removed and approximately 6000g of masterbatch was collected.

[0033] A chlorinated polyethylene, CPE-5, having a chlorine content of20.3 wt. % and a heat of fusion of 2.71 cal/g was prepared in a slurryprocess from a polyethylene having a melt index (I₁₀) of 0.30 dg/minute,substantially according to the procedure described in U.S. Pat. No.4,767,823 and references cited therein. A composition of the invention,Sample 3, was prepared substantially as described in Example 1 by mixing119.42 parts of Masterbatch B and 5 parts of CPE-5. Notched Izod testspecimens were prepared as described in Example 1. Eight test specimenswere broken in tests at both 0° C. and at room temperature and theimpact strength was taken as the average. Sample 3 exhibited anexceptionally good combination of room temperature and low temperatureIzod impact strength along with a rapid fusion rate. The average roomtemperature Izod test value for Sample 3 was 22 ft·lb/in (1.17 kJ/m)with 100% ductile failure. The average 0° C. Izod test value was 2.9ft·lb/in (0.15 kJ/m). Fusion time was 48 seconds for CPE-5.

Comparative Example C

[0034] A chlorinated polyethylene, CPE-6, having a chlorine content of26.1 wt. % and a heat of fusion of 0.26 cal/g was prepared in a slurryprocess from a polyethylene having a melt index (I₁₀) of 1.13 dg/minute,substantially according to the procedure described in U.S. Pat. No.4,767,823 and references cited therein. Comparative Sample C wasprepared substantially as described in Example 3 by mixing 119.42 partsof Masterbatch B and 5 parts of CPE-6. Notched Izod test specimens wereprepared as described in Example 1. Eight test specimens were broken intests at both 0° C. and at room temperature and the impact strength wastaken as the average. Comparative Sample C did not exhibit a goodcombination of impact strength and fusion time. The average roomtemperature Izod test value for Comparative Sample C was 23 ft·lb/in(1.23 kJ/m) with 100% ductile failure. The average 0° C. Izod test valuewas 2.8 ft·lb/in (0.15 kJ/m). Fusion time was 66 seconds for CPE-6.

Comparative Example D

[0035] A chlorinated polyethylene, CPE-7, having a chlorine content of25.5 wt. % and a heat of fusion of 0.18 cal/g was prepared in a slurryprocess from a polyethylene having a, melt index (I₁₀) of 2.45dg/minute, substantially according to the procedure described in U.S.Pat. No. 4,767,823 and references cited therein. Comparative Sample Dwas prepared substantially as described in Example 3 by mixing 119.42parts of Masterbatch B and 5 parts of CPE-7. Notched Izod test specimenswere prepared as described in Example 1. Eight test specimens werebroken in tests at both 0° C. and at room temperature and the impactstrength was taken as the average. The average room temperature Izodtest value for Comparative Sample D was 9.6 ft·lb/in (0.52 kJ/m) with25% ductile failure. The average 0° C. Izod test value was 2.7 ft·lb/in(0.14 kJ/m). Fusion time was 48 seconds for CPE-7.

Comparative Example E

[0036] A chlorinated polyethylene, CPE-8, having a chlorine content of35.5 wt. % and a heat of fusion of 0.17 cal/g was prepared in a slurryprocess from a polyethylene having a melt index (I₁₀) of 2.45 dg/minute,substantially according to the procedure described in U.S. Pat. No.4,767,823 and references cited therein. Comparative Sample E wasprepared substantially as described in Example 3 by mixing 119.42 partsof Masterbatch B and 5 parts of CPE-8. Notched Izod test specimens wereprepared as described in Example 1. Eight test specimens were broken intests at both 0° C. and at room temperature and the impact strength wastaken as the average. The average room temperature Izod test value forComparative Sample E was 24 ft·lb/in (1.28 kJ/m) with 100% ductilefailure. The average 0° C. Izod test value was 2.3 ft·lb/in (0.12 kJ/m).Fusion time was 102 seconds for CPE-8.

What is claimed is:
 1. An impact-resistant composition comprising a) a vinyl chloride polymer and b) an impact modifier, wherein said impact modifier comprises a polymer consisting of a chlorinated olefin polymer having a chlorine content of from 15-39 percent by weight; said chlorinated olefin polymer being prepared from an olefin polymer selected from the group consisting of i) polyethylene homopolymers having I₁₀ values of from 0.05-0.8 dg/minute and ii) copolymers of ethylene and up to 10 mole percent of a copolymerizable monomer, said copolymers having I₁₀ values of from 0.05-0.8 dg/minute; and wherein no more than 1 weight percent of a chlorinated olefin polymer having a weight average molecular weight below 200,000 daltons is present in the impact resistant composition.
 2. An impact-resistant composition of claim 1 wherein the chlorinated olefin polymer has a chlorine content of from 20-30 percent by weight.
 3. An impact-resistant composition of claim 1 wherein the chlorinated olefin polymer is present in an amount between 2 to 20 parts by weight per 100 parts by weight of vinyl chloride polymer.
 4. An impact-resistant composition of claim 1 wherein the chlorinated olefin polymer is prepared from a polyethylene homopolymer having an I₁₀ value of from 0.05-0.8 dg/minute
 5. An impact-resistant composition of claim 1 wherein the chlorinated olefin polymer is prepared from an olefin polymer comprising copolymerized units of ethylene and up to 10 mole percent of at least one ethylenically unsaturated monomer selected from the group consisting of i) C₃-C₁₀ alpha monoolefins; ii) C₁-C₁₂ alkyl esters of C₃-C₂₀ monocarboxylic acids; iii) unsaturated C₃-C₂₀ mono- or dicarboxylic acids; iv) anhydrides of unsaturated C₄-C₈ dicarboxylic acids; and v) vinyl esters of saturated C₂-C₁₈ carboxylic acids.
 6. An impact-resistant composition of claim 5 wherein the unsaturated monomer is selected from the group consisting of propylene; butene; 3-methyl-l-pentene; octene; vinyl acetate; acrylic acid; methacrylic acid; methyl acrylate; methyl methacrylate; and glycidyl methacrylate.
 7. An impact-resistant composition of any one of claims 1 to 5 wherein the chlorinated olefin polymer is a chlorosulfonated olefin polymer.
 8. An impact-resistant composition of claim 1 wherein the vinyl chloride polymer is selected from the group consisting of i) a polyvinyl chloride homopolymer, ii) an interpolymerized copolymer comprising units of vinyl chloride and up to 20 weight percent units of at least one additional comonomer, and iii) a graft copolymer of vinyl chloride grafted to an ethylene-containing polymer.
 9. An impact-resistant composition of any one of claims 1 to 6, or 8, further comprising c) at least one additional polymeric component, wherein the additional polymeric component is selected from the group consisting of acrylonitrile butadiene styrene copolymers and acrylate polymers.
 10. An impact-resistant composition of claim 9, wherein said acrylate polymer is selected from the group consisting of methacrylate butadiene styrene copolymers and polyacrylates.
 11. An impact-resistant composition of claim 9 wherein the additional polymeric component is present in an amount up to 200 parts by weight per 100 parts by weight of the chlorinated olefin polymer. 